Sick, sick SICK to my stomach

This is suck a very long story, I am not sure I can condense it well. 

I got married last summer. We were both divorced for a long time.I don't like my ex much.  He is still friends with his.  And mostly, I am OK with that. I mean, it is just good for the kids. It is hard though. 

Before we got married, they still talked 3-4 times a week.  Literally to the day we got married. Then nothing.   If she needed something, she would give me a message for him on Facebook. 

Until suddenly, this week, two lengthy phone calls on his cell (I get the bill) from a blocked number.  Honestly, yes, I am assuming it was her.

I get it that they may talk on occasion.  But he never mentioned it.  Their kids are grown..... no need for major communication.  (Am I being petty??)

I dont want to say anything -- dont want him to think I am checking on purpose. But this is really killing me.